% -------------------------------------------------------------------------
% state parameters
%
% auxdata = statement_
%
% Input argumuents:
% -------------------------------------------------------------------------
% None
%
% Output argumuents:
% -------------------------------------------------------------------------
% auxdata        [structure]         parameters            [  -  ]
%
% External functions called:
% -------------------------------------------------------------------------
% None
%
% Copyright(C) 2015/06/30 by Chen Zhang, 
% School of Astronautics, Beihang University
% chenzhang.buaa@gmail.com
% -------------------------------------------------------------------------
function auxdata = statement
mu = 1.21506683e-2; % Earth-Moon gravitational constant (--)
Isp = 3000; % Specific impulse (s) 
g0 = 9.80665; % Gravitational acceleration (m/s^2)
Tmax = 20; % Maximum thrust force (N, kg*m/s^2)
m0 = 1500; % Initial mass (kg)
tol = 1e-10; % Integration tolerance
% -------------------------------------------------------------------------
LU = 3.84405e5; % dimensional values of length (km)
TU = 3.7567696752e+005; % dimensional values of time (s)
VU = 1.02323281; % dimensional values of velocity (km / s)
MU = m0; % Mass unit (kg)
auxdata.LU = LU;
auxdata.TU = TU;
auxdata.VU = VU;
auxdata.MU = MU;
% -------------------------------------------------------------------------
% Scaling
Tmax = Tmax * 0.001 * TU^2 / (MU * LU); % Maximum thrust force (dim.less)
Isp = Isp / TU; % Specific impulse (dim.less)
g0 = g0 * 0.001 * TU^2 / LU; % Gravititational acceleration (dim.less)
c = Isp * g0; % Exhaust velocity (dim.less)
auxdata.mu = mu;
auxdata.Tmax = Tmax;
auxdata.c = c;
auxdata.tol = tol;
end
% -------------------------------------------------------------------------
